package com.ss.security;
import java.util.Collection;
import java.util.Iterator;

import org.springframework.security.access.AccessDecisionManager;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.access.SecurityConfig;
import org.springframework.security.authentication.InsufficientAuthenticationException;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.stereotype.Component;

/**
 * 访问决策器
 * 如果不存在对该资源的定义，直接放行；否则，如果找到正确的角色，
 * 即认为拥有权限，并放行，否则throw new AccessDeniedException("no right") 403页面;
 */
@Component("myAccessDecisionManagerBean")
public class MyAccessDecisionManager implements AccessDecisionManager {

    //In this method, need to compare authentication with configAttributes.
    // 1, A object is a URL, a filter was find permission configuration by this URL, and pass to here.
    // 2, Check authentication has attribute in permission configuration (configAttributes)
    // 3, If not match corresponding authentication, throw a AccessDeniedException.
    public void decide(Authentication authentication, Object object,
             Collection<ConfigAttribute> configAttributes)
            throws AccessDeniedException, InsufficientAuthenticationException {
        if(configAttributes == null){
            return ;
         }
         System.out.println(object.toString());  //object is a URL.
         Iterator<ConfigAttribute> ite=configAttributes.iterator();
        while(ite.hasNext()){
             ConfigAttribute ca=ite.next();
             String needRole=((SecurityConfig)ca).getAttribute();
            for(GrantedAuthority ga:authentication.getAuthorities()){
                if(needRole.equals(ga.getAuthority())){  //ga is user's role.
                    return;
                 }
             }
         }
        throw new AccessDeniedException("no right");
     }

     @Override
    public boolean supports(ConfigAttribute attribute) {
        // TODO Auto-generated method stub
        return true;
     }

     @Override
    public boolean supports(Class<?> clazz) {
        return true;
     }


}
